Combined regenerator and precooler for gas turbine cycles



s. HOLM 2,650,073

COMBINED REGENERATOR AND PRECOOLER FOR GAS TURBINE CYCLES Aug. 25, 1953 2 (Sheets-Sheet 1 Filed June 25, 1949 WATER LOW TEMP H/6H 39555.

IN 1 PW CR Sven o/m rro/e/vzsy llll |L If- Aug. 25, 1953 s HOLM 2,650,073

COMBINED REGENERATOR AND PRECOOLER FOR GAS TURBINE CYCLES Filed June 25, 1949 2 SheetsSheet 2 VE/QT/CAZ POSITION l/o/e/zo/vrAL AX/AL' P057770 PEGL- ERA 7' 0R FEE CO0LE Cave/NED REGENEPATOR PR5 (00052 COMB/NED COMB/NED V 4 8 FLOW CHANGES IN VEN TOR. Sren b /m BY A ' v rap/v0 Patented Aug. 25, 1953 COMBINED REGENERATOR AND PRECOOLER FOB GAS TURBINE CYCLES Sven Holm, Wellsville, N. Y., assignor to The Air Preheater Corporation, New York, N. Y.

Application June 25, 1949, Serial No. 101,458

3 Claims. 1

The present invention relates to heat exchange apparatus and particularly to a combined regenerator and precooler for gas turbine cycles in which the heat exchangers are essentially of the plate type for effecting heat transfer between two fluids.

In a semi-closed gas turbine cycle the working fluid is not exhausted to the atmosphere but subsequent to expansion through the turbine is directed through a set of alternate passages in a so-called regenerator where it gives off heat to the high pressure working fluid that comes from the compressor and traverses the other set of passages which are separated from those of the first set by metal plates that form the passage walls. After discharge from the regenerator the working fluid must be further cooled before being compressed, which operation is carried out in a precooler that ordinarily utilizes water as the cooling medium. The present invention contemplates the combination into a single unit of the precooler and regenerator components with resulting decrease in the weight of the apparatus and the space that it occupies. In addition this affords other advantages, such as a marked decrease in the amount of insulation required around the apparatus in order to make conditions tolerable for operatives in the engine room.

The above and other features and advantages of the invention become apparent upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which: 7

Figure 1 is a longitudinal sectional view mainly diagrammatic in form through heat exchange apparatus embodying according to the present invention a combination of a regenerator component with a precooler component.

Figure 2 is a sectional view on an enlarged scale as seen upon the line 2-2 in Figure 1.

Figures 3, 4, 5 and 6 are diagrammatic views illustrating the savings in weight, space occupied, amount of insulation required and pressure drop through the unit when the regenerator and precooler are combined in accordance with the present invention as contrasted with separate units.

In the drawings, the numeral 10 designates the exterior casing of the combined regenerator and precooler unit which in the form shown is of generally cylindrical construction. The high temperature low pressure fluid coming from the turbine is admitted to the regenerator through the inlet connection 12 and flows into the central space [4 of the unit passing in an axial direction towards the baffle plate I6 that closes off the remote end of the central space l4. Immediately surrounding the central space H! is the annular regenerator section which consists of radially extending spaced plates 2| which form alternate passages designated 22 for radial flow of the low pressure fluid with intermediate passages 23 providing for flow in an axial direction of the high pressure fluid. The high temperature, low pressure fluid flowing axially of the central space [4 toward baffle plate It turns and flows at right angles and in a radial direction through the passages 22. The low temperature fluid enters the outer half 30 of the annular header 3! at the left hand end and the regenerator section 28 through the inlet 32 flowing axially through the passages 23 of the first pass 33 and then reverses its direction in header 29 at the right hand end of the regenerator section 20 to flow back through the second or inner pass 34 to the left hand end of the passages 23 thereof and into the inner half 35'of the annular header 3! from which it is discharged from the regenerator through the outlet connection 36.

After passing radially outward through the passages 22 of the regenerator section 20 the partly cooled low pressure fluid enters the intermediate chamber 40 to be distributed to the inner ends of the passages 22C in the precooler section 4! and flowing into the plenum space 42 between the precooler section 4| and the casing l0 flows axially towards the end'of the casing to the collector chamber 43 and is discharged through the outlet connection 44. Cooling water enters the outer half of the annular header 5| at the left end of the precooler section 4i through the inlet 52 to be eventually discharged from the outlet connection 53 at the left after having flown axially through the intermediate passages 23C of the precooler section 4| in several axially ex tending passes 54 and 55 thereof just as is the case with the axial flow of the low temperature high pressure fluid through the regenerator section 20.

For the purposes of obtaining more efficient heat transfer between the fluids traversing the regenerator, the walls of the passages 22 for the low pressure fluid are provided with extended surface. On the walls of the passages 22 for the low pressure fluid this extended surface may consist of pin fins made of looped wire as disclosed in the application filed in the name of Sven Holm et a1. under Serial No. 752,008 on June 3, 1947, now Patent No. 2,595,457, granted May 6, 1952, while the high pressure passages 23 have channel members 6! or alternatively strip fins extending in the axial direction of fluid flow.

In operation the low pressure gas coming from the turbine at high temperature say 1150 F. flows axially of the central space It and then radially through the passages 22 of the regenerator section 25 and enters the passages 22C of the precooler section 41 at 575 F. before again changing direction to flow axially of the plenum space 42 between the precooler M at say F. and the casing 10. Here because the low pressure fluid makes but four changes in direction departing from its initial axial flow in the can-. tral space I4 flrstly to a radial flow inthe pas-1 sages 23 and 23C, secondly axially of the plenum space 42 and, thirdly, inwardly in a radial direction in collector 43 before finally turning axially outward to and through the outlet connection 44 at the right hand end of the unit. As indicated in the diagram of Fig. 6 there are but four changes of direction with the present combined regenerator and precooler as compared with eight flow changes when the two components are in separate units connected in series relation with the result that the pressure drop caused by changes in direction of flow is reduced by approximately 50%. Fig. 3 indicates diagrammatically that a saving of 25 to 30% in the floor space occupied by the regenerator and precooler is achieved when combined in accordance with the invention as compared with separate units in vertical positions or separately in series relation. Likewise, there is a saving in weight of approximately 15% as indicated in Fig. 4 due in part to the fact that a single enclosing casing ill is required for the two com bined units 29 and 4!. Further, because of the fact that with the precooler section 4! surrounding the regenerator section 29 the temperature of gases which have been reduced to say 575 F. at intermediate chamber 49 in passing through the regenerator 29 are cooled to the very much lower temperature of approximately 85 F. after passing through the surrounding precooler section 4| into plenum 42. This results in re"- ducing the amount of insulation required for the apparatus by substantially 90% as indicated in Fig. 5 which also illustrates that substantially less ventilation is required for the surrounding space in the engine room. All of these factors involving (a) savings in space occupied, (in) weight of apparatus, (c) insulation and (d) surrounding temperature conditions are of major importance when such apparatus is required for use in mobile vehicles or vessels wherein considerations of space and weight are often of the utmost importance.

What I claim is:

1. In heat exchange apparatus for use in gas turbine cycles or the like; a regenerator comprising: a hollow centered heat exchanger core having inner and outer sets of axially extending passages for a gaseous fluid to be heated and a transverse set of passages for a relatively hotter gas extending from the central space of the core to its outer margin; means for admitting fluid to be heated to the outer set of axial passages at one end thereof; means forming a header at the opposite end of said core for connecting the inner and outer sets of axial passages in series flow relation; an outlet header connecting with the outer set of passages at the other end of the core; means forming an inlet for admitting the heating gas to the central space within said core at said one end; a precooler comprising a second hollow centered core closely embracing the first and having transverse passages for flow of the heating gas aligned in series flow relation with the transverse passages of the first core and inner and outer sets of axially extending passages interconnected for fiow of a cooling fluid in similar manner to that in said regenerator; a casing surrounding said second core in spaced relation thereto to form a header chamber for gas discharged from the transverse passages of said second core; and an outlet chainher in said casing beyond said core closure and communicating with said last header chamber; and an ofitake leading axially from said outlet chamber.

2. In a heat exchange apparatus for use in gas turbine cycles or the like; a regenerator comprising; a hollow centered heat exchanger core having axially extending passages for the gaseous fluid to be heated and a set of transverse passages for a relatively hotter gas extending from the central space of the core to its outer margin; means for admitting fluid to be heated to the axial passages; an outlet header connecting with the axial passages of the core; means forming an inlet for admitting a heating gas to the central space within said core at one end; a precooler comprising a second hollow centered core closely embracing the first and having transverse passages for fiow of the heating gas aligned in series flow relation with the transverse passages of the first core and axially extending passages for flow of a cooling fluid; a casing surrounding said second core in spaced relation thereto to form a header chamber for gas discharged from the transverse passages of said second core; and an outlet chamber in said casing beyond said core closure and communicating with said last header chamber; and an offtake leading axially from said outlet chamber.

3. In heat exchange apparatus for use in gas turbine cycles or the like; a regenerator com prising: an annular heat exchanger core having inner and outer sets of axially extending passages for the gaseous fluid to be heated and a transverse set of passages for a relatively hotter gas extending from the central space of the core to its circumferential margin; means for admitting fluid to be heated to the outer set of axial passages at one end thereof; means formr ing a header at the opposite end of said core for connecting the inner and outer sets of axial passages in series flow relation; an outlet header connecting with the outer set of passages at the other end of the core; means forming an inlet for admitting the heating gas to the central space within said core at said one end; a precooler comprising a second annular core closely embracing the first and having transverse passages for fiow of the heating gas aligned in series now relation with the transverse passages of the first core and inner and outer sets of axially extending passages interconnected for flow of a cooling fiuid in similar manner to that in said regenerator; a circular casing surrounding said second core in spaced relation thereto to form an annular collecting chamber for gas discharged from the transverse passages of said second core; and an outlet chamber in said casing beyond said core closure and communicating with said annular collecting chamber; and an oiltake leading axially from said outlet chamber.

SVEN HOLM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,917,275 Rossman et al July 11, 1933 2,170,145 Kooistra Aug. 22, 1939 2,222,496 Belaiefi et al. Nov. 19, 1940 2,236,750 Cross Apr. 1, 1941 2,316,273 Meyer et a1 Apr. 13, 1943 2,372,079 Gunter Mar. 20, 1945 2,421,371 Budlane June 3,1947 2,423,175 Churchill et a1 July 1, 1947 2,430,227 Jensen et al. Nov. 4, 1947 FOREIGN PATENTS Number Country Date 353,087 Great Britain July 23, 1931 688,634 France May 13, 1930 

